August 22, 2012

Human Skull Discovery Forces Rethink On Modern Man’s Migration

A human skull that was recently found in Southeast Asia provides new details in the story of modern man´s migration out of Africa, through Asia, and beyond to the Pacific.

While anthropologists have long theorized that humans emerged from Africa and into East and Southeast Asia around 60,000 years ago, there has been a significant lack of fossil evidence to support these claims. The earliest skull fossil evidence in the region had dated back 16,000 years and was found in the early 20th century.

The newly found skull, which dates to between 46,000 and 63,000 years old, bolsters genetic studies that point to modern humans inhabiting Laos and the surrounding environs at that time, according to a report of the anthropological discovery published in the latest edition of the Proceedings of the National Academy of Sciences (PNAS).

University of Illinois anthropology professor Laura Shackelford explained that the fossil she and her colleagues found is a game-changer when it comes to the human fossil record of Southeast Asia.

“It´s a particularly old modern human fossil and it´s also a particularly old modern human for that region,” said Shackelford, who led the study along with anthropologist Fabrice Demeter, of the National Museum of Natural History in Paris.

“There are other modern human fossils in China or in Island Southeast Asia that may be around the same age but they either are not well dated or they do not show definitively modern human features,” she added. “This skull is very well dated and shows very conclusive modern human features.”

Anthropologists could not say if the cave that the skull was found in is either a dwelling or burial site because no other artifacts were discovered alongside it. According to Shackelford, the person likely died outside the cave and was washed into it at some later point.

To zero in on an exact date for the fossil, the research team used radiocarbon dating and luminescence techniques to determine the age of the soil layers higher than, underneath and surrounding the remains, which were found about 8 feet below the surface of the cave. According to the luminescence analysis performed by Kira Westaway of the Macquarie University in Australia, the soil surrounding the fossil had washed into the cave between 46,000 and 51,000 years ago.

“Those dates are a bit younger than the direct date on the fossil, which we would expect because we don´t know how long the body sat outside the cave before it washed in,” Shackelford said.

A morphological and dental analysis of the skull showed a differentiation from ancient western Eurasian humans. This also suggests that the fossil belongs to a unique population living in Southeast Asia 60,000 years ago.

“This fossil find indicates that the migration out of Africa and into East and Southeast Asia occurred at a relatively rapid rate, and that, once there, modern humans weren´t limited to environments that they had previously experienced,” Shackelford added. “We now have the fossil evidence to prove that they were there long before we thought they were there.”